[RFC] msgtime: do not require tz offset with Date::Parse fallback

[Eric Wong]

Leah Neukirchen <l...@vuxu.org> wrote:
> Hi,
> 
> I've recently imported some sizable archives (~100k messages) of old
> mailing lists and noticed some slight inconveniences:

Thanks for the reports, will answer 2. separately.

> 1) RFC5322/822 invalid Date: headers should be parsed more gracefully
> 
> Some old mails had Date: headers without time zones, e.g.
> Date: Sat, 27 Sep 1997 10:02:32
> 
> This results in public-inbox asserting this is the current date.
> But this assumption makes no sense (literally every other guess
> would be more likely), and also results in these messages showing up
> on the first page of the archive.  Furthermore, sorting is then not
> stable, pressing F5 make the threads jump around.  I'd recommend
> falling back to +0000 instead.

I think a fallback to +0000 makes sense, too.
It's not a new bug in 1.3.0 (which makes Date::Parse optional).

Looks like that regression was introduced a while ago in
commit ae80a3fdb53d70142624f2691ed8ed84eddda66b
("MsgTime.pm: Use strptime to compute the time zone")

Cc-ing Eric W. Biederman in case he has any input on this.

Now, I'm not sure if this fallback is worth adding for users
without Date::Parse.  The non-Date::Parse path is a bit faster
and optimized for common (correct) dates...

------------8<------------
Subject: [RFC] msgtime: assume +0000 if TZ missing when using Date::Parse

Reported-by: Leah Neukirchen <l...@vuxu.org>
Link: https://public-inbox.org/meta/87h7zfemur....@vuxu.org/
Fixes: ae80a3fdb53d7014 ("MsgTime.pm: Use strptime to compute the time zone")
---
 lib/PublicInbox/MsgTime.pm | 3 ++-
 t/msgtime.t                | 7 +++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/PublicInbox/MsgTime.pm b/lib/PublicInbox/MsgTime.pm
index 8eee9a75..8703d7bc 100644
--- a/lib/PublicInbox/MsgTime.pm
+++ b/lib/PublicInbox/MsgTime.pm
@@ -104,7 +104,8 @@ sub str2date_zone ($) {
                # off is the time zone offset in seconds from GMT
                my ($ss,$mm,$hh,$day,$month,$year,$off) =
                                        Date::Parse::strptime($date);
-               return undef unless(defined $off);
+               return unless defined($year);
+               $off //= 0;
 
                # Compute the time zone from offset
                my $sign = ($off < 0) ? '-' : '+';
diff --git a/t/msgtime.t b/t/msgtime.t
index 5c4636a2..7c95e547 100644
--- a/t/msgtime.t
+++ b/t/msgtime.t
@@ -5,6 +5,8 @@ use warnings;
 use Test::More;
 use PublicInbox::MIME;
 use PublicInbox::MsgTime;
+use PublicInbox::TestCommon;
+
 our $received_date = 'Mon, 22 Jan 2007 13:16:24 -0500';
 sub datestamp ($) {
        my ($date) = @_;
@@ -102,6 +104,11 @@ is_datestamp('Thu, 14 Dec 2006 00:20:24 +0480', 
[1166036424, '+0520']);
 is_datestamp('Thu, 14 Dec 2006 00:20:24 -0480', [1166074824, '-0520']);
 is_datestamp('Mon, 14 Apr 2014 07:59:01 -0007', [1397462761, '-0007']);
 
+SKIP: {
+       require_mods('Date::Parse', 1);
+       is_datestamp('Sat, 27 Sep 1997 10:02:32', [875354552, '+0000']);
+}
+
 # obsolete formats described in RFC2822
 for (qw(UT GMT Z)) {
        is_datestamp('Fri, 02 Oct 1993 00:00:00 '.$_, [ 749520000, '+0000']);
--
unsubscribe: one-click, see List-Unsubscribe header
archive: https://public-inbox.org/meta/